Lighting Thermal pads vs grease

[budelee]

Mang,i wish somebody woulda started this thread before i built mine.....so are you guys saying that if to much is used its not efficient??? And the cobs will fail early?? Ive noticed that my heatsinks are warm to the touch but not hot,and there was concern over me running a steel frame rather than aluminum due to heat,but the frame is cool to the touch..should i check it with a digital temp gun??

 

[BigSm0]

Mang,i wish somebody woulda started this thread before i built mine.....so are you guys saying that if to much is used its not efficient??? And the cobs will fail early?? Ive noticed that my heatsinks are warm to the touch but not hot,and there was concern over me running a steel frame rather than aluminum due to heat,but the frame is cool to the touch..should i check it with a digital temp gun??

Once you tighten down the cob any excess is pushed out. It's just a bit messier. With 57watt heatsinks with cobs running 43 watts you are probably going to see well over 100k hours from the cobs

 

[budelee]

Once you tighten down the cob any excess is pushed out. It's just a bit messier. With 57watt heatsinks with cobs running 43 watts you are probably going to see well over 100k hours from the cobs

Whats up smo!! I kinda thought that,and i am running a bit less wattage cause there's 5 cobs..what @Ripper had said about the steel frame/heat just had me thinking about it

 

[Tanglefoot]

My two questions when I started this thread were to find out what methods people were using & whether these methods stood the test of time. The methods are here but no one has answered whether their method has worked well over a long period of constant use, like I said though perhaps no one has got there yet??

 

[BigSm0]

Just got done reading up on the testing they do with these cobs. Besides major personal failure I haven't seen a single cob burn out. I also checked last night while placing another cob order how many empty trays I have. 9x50 and all of them are perfect.

To help answer your question I have a thermal pad light that's run for a year and still doing well on undersized heatsinks. The rest are with grease/paste and they are all perfect and running cool as well.

 

[KsjAuto]

2-3 years running with thermal adhesive cheap Chinese stuff oem. No problems. lights running 2c above ambient temp. [emoji2]

[emoji3]

 

[Puddentane]

My two questions when I started this thread were to find out what methods people were using & whether these methods stood the test of time. The methods are here but no one has answered whether their method has worked well over a long period of constant use, like I said though perhaps no one has got there yet??

I think we are spitting hairs here.

All methods will work adequately. We are not looking at a situation where one of them is abject failure. The convenience of pads is the reason they are a good choice for those that are starting out. If you have a background working with electronics then you know that the differences can be striking when you push out to the last 5-10% of a circuits capabilities. But we don't work out there. The chips that we get from the manufacturers are spec'd in manufacturing to take a minimum of the rating for the chip. Many can take much, much more.

Relax. Choose a method that is easy for you. IF you choose to use paste just get a nice even thin layer across the back of your chip and give it a gentle twist on the sink before you screw her in. For the vast majority of us we will never see failure due to a thermal event provided we used something and got a good seat.

And the Cobs are well worth the confusion.

 

[Tanglefoot]

Thanks for that, you make some good points. However, I don't have much £$ to fork out on chips if they fail & so finding out the best method of application through other people's experience is a worth while endeavour, why not be as thorough as possible? Like I said, on another forum I have seen pictures of a failed cob due to the inconsistent way the paste was applied, their method caused tiny air pockets which in time fried the cob.

As far as I can see the best way you can apply the paste is to dab a small rice like sized amount in the middle, depending on the size of the cob, then push down & twist a few times. This way eliminates as far as possible any air pockets so it seems.
Had a feeling this might be a somewhat contentious issue

 

[Ripper]

Whats up smo!! I kinda thought that,and i am running a bit less wattage cause there's 5 cobs..what @Ripper had said about the steel frame/heat just had me thinking about it

I think you are good to go bud.. especially if your frame is cool to the touch.. I was pushing 75 watts to each cob big difference

 

[thetreeman]

Paste > pads unless you dont feel competent enough to properly apply the paste, then go for the pads. Paste also is much cheaper than pads if you apply it correctly, which could be a factor for some.